Feeding device for sheets



April 1934- Y M. VIERENGEL 1,956,140

FEEDING DEVICE FOR SHEETS Filed Feb. 28, 1931 3 Sheets-Sheet l I N VEN TOR.

Mam-13w V'IERENEEL- a arrow/EV.

April 24, 1934. vlERENGEL 1,956,140

FEEDING DEVICE FOR SHEETS Filed Feb. 28, 1951 3 Sheets-Sheet 2 INVENTOR. MHTTHEW VIEEENEEL- BY E - ATTORNEY.

April 24, 1934. WERENGEL 1,956,140

FEEDING DEVICE FOR SHEETS Filed Feb. 28, 1931 3 Sheets-Sheet 3 INVENTOR.

Y MET THEWVIERENEEL ATTORNEY Patented Apr. 24, 1934 T FHQE FEEDING DEVICE FOR SHEETS 'Matthew Vierengel, Brooklyn, N. Y., assignor to M. Vierengel Machine Co. Inc., Brooklyn, N. Y., a corporation of New York Application February 28, 1931, Serial No. 519,056 23 Claims. (Cl. 271-4) My invention is a sheet feeding device and more stack of sheets, during the repeated removal of particularly a device which is used in combination the top Sheet f om Sa d ta with machinery working upon, or handling sheets O e m r Obj of y invention is to provide c-f flexible material, my device serving for feeda smoothly functioning feeding device for nv 5; ing sheets into such a machine from a, stack of lope blanks which may be associated with the iman sheets of flexible material, proved creasing and folding means described in The purpose of my invention is to provide for y application Serial 6 ,348, May 4th, 1929, a better and more careful handling of the sheet n t d E v p m such an association material during th feeding ti th on serving to enhance the production of an envelope '10- one hand making the feeding mechanism more machine, qualitatively, quantitatively, and 81130 65 reliable and allowing its operation at a greater in respect to the Variety Of enVelOpeS Which can feeding speed, and on the other hand permitting he made y that maehlhe, as to the Size of envethe safe feeding of the very thinnest sheet matelODeS and as to the thinness of S ock us drials, for instance large sheets of glassine. These and other Objects of y Ve t D W l One object of my invention is to provide a feedhe more fully understood from e win (16- 7o ing mechanism for sheet material, which is seriptioh d ppe d d draw n s, i which I mounted at th fr m; of d d t of th show, exemplarily, a sheet feeding device as used machine which it is to cooperate with, into which in Connection With an envelope making machinethe stack of paper may be fed from the front of The frame of y feeding device forms p r 0f 20 the machine, and in which the stack of paper the frame of the envelope making c e a d 75 is arranged upon the outside of the machine withis broken a d t d i where t in the easy reach and within the constant 010- ehvelope making machine p pe nd to he servation of th operator left of my feeding device (Fig. 1). The envelope Another object of this invention is to provide making machine y he of the yp Shown in means, which separate a sheet from a stack of y Patent granted August 90 sheets, or by which it is lifted, to a greater ex- 1911, and entitled Envelop machine A 1 tent, from such stack of sheets before the sheet a ty of the pa t of m vi are more l y is laterally removed from above the said stack described in that p Flg. 1 shows a (left) side view of a feeding of papers.

Another object of this invention is to provide device of y inventionmeans by which a sheet is evenly and gradually 2 ShOWS a COI'TBSpOHdlHg front w. lifted off a stack of sheets of flexible material. F 3 shows a t p V ew Of e tac of sheets Another object of my invention is to provide and the machine part Working t e f t e means in connection with a device for feeding e a Of the p Sheetsheets from a stack of sheets, which lift the top ig- S W in a Corresponding (left) Side w, 9 sheet of said stack without in any manner buckthe details of my sheet-raiser.

ling, indenting or otherwise marking or defacing Fig. 5 shows an enlarged detail view of the said sheet. right side of my device.

A further object of my invention is to provide Fig. 6 shows a detail (left) side view of the means for lifting a sheet from a stack of blanks gripper cylinders, in which the respective operin such a manner, that its edge is fully exposed ating cams are schematically indicated. This for the engagement of gripping means which view illustrates a sheet passing from one cylinder serve to remove said sheet from said stack. to the other.

A further object of this invention is to provide Similar numerals refer to similar parts through a device for feeding sheets from a stack of sheets, the several views. in which the sheets are disposed substantially in The gears by means of which the spools, cylinthe same direction when they are delivered by ders and discs of my feeding device connect to said device, as they are arranged in said stack. each other and to the mechanism of my feeding Another object of my invention is to provide machine are on the right side of the device (Fig.

a plurality of gripper cylinders in a device for 2). A shaft 11, journalled in the two sides 12 feeding sheets from a stack of sheets, the sheets and 13 of the frame, carries a gear 14 which conbeing brought into perfect registry while passing nects backwardly to the driving mechanism of from one of said cylinders to the other. the envelope making machine (not shown) and Still another object of my invention is to prewhich frontwardly connects to the gear 15 which 5 serve the alignment of the sh ts making up a is mounted on a shaft 16 and which drives the upper gripper cylinder 17. Gear 14 also drives the gears and 21 on the feed rollers 18 and 19 (not shown in Fig. 2) which are respectively mounted on the shafts 22 and 23 and by means of which the sheets are fed from the upper gripper cylinder 17 out of the feeding device into the envelope making machine. The gear 15 on the upper gripper cylinder 1'7 meshes with a gear on the friction roller shaft 24, on which the friction rollers 25 are mounted, said friction rollers having the same circumferential speed as the gripper cylinder 17 and the feed rollers 18 and 19.

Towards the front of the machine, the gear 15 on the upper gripper cylinder 17 is connected to gears 26 and 27 which are journalled upon the frame in shafts 28 and 29, and which, respectively, drive the paste applying disc 30 and the paste roller 31. lhe paste roller 31 is submersed in the paste reservoir 32, which is suspended from a cross base 33, extending across the machine. The paste applying disc 30, and the paste roller 31 are also driven at the same circumferential speed as the upper gripper cylinder 17. So is the lower gripper cylinder 34, which is geared by gear 35 to the gear 15, which drives the upper cylinder 17. The shaft 36 of the lower gripper cylinder 34 carries a sprocket and chain drive 37 on the left side of the machine, by means of which it is connected to the cam shaft 38.

Whereas the shafts 11, 16 and 22 are journalled at fixed positions in the frame, the other shafts 23, 24, 28, 29 and 36, which are connected to these shafts by gears, and which carry cylinders, rollers or discs of diameters substantially equal to the pitch diameters of the respective gears, are adjustably mounted in the frame, so that they may be set for accurate cooperation with the other shafts in the work to be performed by the respectively carried parts. Thus shaft 23 may be adjusted towards shaft 22, and shafts 24 and 36 towards shaft 16, in order to facilitate the engagement of the sheets between the respective rollers or cylinders. Shaft 29 can be adjusted towards shaft 28, to provide for the appropriate transfer of paste from roller 27 to disc 30, and the latter is adjustable towards the cylinder 17 for the regulation of the application of paste from the disc to the blank travelling on cylinder 17.

The lower gripper cylinder shaft 36 and the shaft 38, are driven at a speed synchronized to that of the shaft 16 of the upper gripper cyl nder 18 but they both. rotate in a direction opposite to that upper gripper cylinder. Each revolution of these parts represents a cycle of the operation of my device.

Into the sides 12 and 13 of the frame extend two parallel, angularly disposed round rods 39 and 40, respectively, upon which is slidably arranged the elevator 41. It carries a plurality of longitudinal planks 42 which support the stack of sheets 43. The sheets of stack 43 are, in this illustration of my invention, envelope blanks; the top sheet 44 shows in the top view of Fig. 3. The stack of envelopes rests upon the inclined elevator 41, th envelope blanks resting at the lower back end against the inclined square 45, which are set to fit into corners between adjoining flaps 46 and 47 of the envelope. The two bars are transversely slidably hung ontoa fiat cross bar 43 and they carry lugs 49 which are oppositely tapped and which are engaged upon the right and left hand screw parts of the shaft 50, respectively. The shaft 50 is journalled upon the frame and carries a hand wheel 51 upon its end, by the rotation of which the bars 45 may be moved towards or away from each other in parallelism, so that they can be set to fit into the corners between the flaps of envelope blanks of various sizes.

The two rods 39 and 40 carry two brackets 52 and 53. The former rotatably support the elevator operating shaft 54, the latter brackets 53 carry a stationary rod 55, which is provided with a feather key-way 56. Two brackets with extension arms 57, which are disposed parallel to the elevator top, are transversely slidably arranged upon the rod 55 and engage upon the feather key-way 56, so that the arms remain in parallelism and may be set at any distance apart. The arms 57 carry brackets 58 which are longitudinally slidably upon said arms and from which downwardly extend the pins 39 which serve to keep the flaps 60 of the envelope blanks in alignment and for which I provide suitable clearance holes in some of the planks 42.

On bolts 61 extending from the left and right side of the elevator 41 are fastened chains 62 and 63 which endlessly extend over a pair of similar sprockets mounted on shaft 54 and over a pair of idler sprockets mounted in the rods 39 and 40 near the lower ends thereof. By clockwise or counter-clockwise rotation of shaft 54 the elevator is therefore raised or lowered. The ratchet 64 on shaft 54 is engaged by a stop pawl 65 which retains the elevator at a given height, and by the pawl 66 extending thereo-nto from the cam lever 67, which is actuated by cam 68 on shaft 16 on each revolution of said shaft. However, the pawl 66 engages upon the ratchet 64 only when the flat, circularly disposed member 70- which is hinged upon the free end of lever 71, which in turn is journalled upon shaft 54-is in the position of Fig. 1. When the elevator has been raised to a height, at which the top sheet 44 of the stack of sheets 43 is at the desired distance from the gripper cylinder 35, the lever 71 is swung in clockwise direction, and the flat member is interposed between the pawl 66 and the ratchet 64, so as to prevent the pawl from engaging upon said ratchet, by means of the following mechanism:

The lever 71 is operatively connected by a link 72 to the lever 73, which is fixedly mounted upon the end of a shaft 74. The shaft extends transversely to the elevator, and it is rotatably mounted upon the rods 39 and 40. Two levers 75 are mounted upon the shaft 74. In the free ends of these levers is journalled the shaft 76, which carries, by means of suitable lugs 77, the bar 78. That bar rests upon the stack 43 and is curved up in front and in the back, so as not to cut the top sheet 44. When bar 78 is raised by the stackas said stack is raised with the elevator by engagement of pawl 66 on ratchet 64,the shaft '74 is rotated, lever 73 is swung up and causes the flat member 70 to slide between pawl 66 and ratchet 64, thus intercepting the raising operation of the elevator. But, after a certain number of sheets have been removed from the stack 43, the bar 78 drops so low as to withdra by means of the intermediary operative connection, member 70 from between the pawl 66 and the ratchet 64; whereupon the latter is rotated again and the top sheet 44 is raised to the proper height. Pawl 66 normally faces the flattened side of a small hand wheel 79. When the ratchet 64 is to be manipulated, (for lowering the elevator) the operator rotates that handwheel, and pawl 66 and pawl (by means of extension are lifted out of engagement with the ratchet.

Fig. 5 shows that the free end 81 of a cam lever 82, which is fulcrumed upon the side 13 of the frame and cyclically operated by the cam 83 on the end of cam shaft 38, engages upon a roller 84 on the end of shaft 76 and lifts the bar 78 from the stack 43 above the level 85 of the top thereof, each time a top sheet 44 is to be removed therefrom.

When the sheet material is very light, care must be taken that the rising and falling bar 78 does not push the sheet frontwardly and backwardly. The bottom of the bar must therefore be disposed parallel to the stack of sheets and it must remain parallel thereto when lifted from the stock and must be lifted substantially at right angles to the stack. For that purpose a lever 86, which carries a roller 87 at its free end, is fastened upon the shaft 76. That roller travels in a slot 88 in plate 89 which is mounted on rod 40, that slot being so disposed that it guides the plate 78 parallel to itself, while the shaft '76 is swung by lever 75 around shaft 74.

The pick-up device shown in the drawings is of the suction type and functions substantially in the manner of the corresponding parts shown in my prior patent. The device proper comprises a hollow body 90, the rear end of which is attenuated and is connected by a rubber hose 91 to a valve (not shown) which is operated cyclically from the cam shaft 38, said valve being connected to a pump (not shown) which provides the suction required for the pick-up device. The cam operated valve alternatively connects the suction means to the pump or to the air, according to whether the suction means are to hold or to release the top sheet 44. The suction body is provided with a suction head 92 at its front end. The head is suitably shaped and perforated downwardly, so that it can pickup the top sheet 44 when brought into abutment therewith and when connected with the pump; it will release that sheet when air is admitted to it.

The suction 90 is connected by a system of intervening links and levers to a supporting rod 93 on the frame, and to the lever 94 which is longitudinally slidably retained upon the cam shaft 38. The lever 94 engages upon a cam on shaft 38 and takes care of the longitudinal oscillations of the suction means, whereas other cam levers 95, which are also operated from the cam shaft 38, bring about the vertical and tilting movements of the suctions means.

The suction means are normally in a position backwardly removed from the stack of sheets 43. They are brought, by cam action, forward into a position where the head 92 extends over the top sheet 43. The head is then lowered and picks up the top sheet, suction being applied from the pump. The head is raised again. holding the top sheet until the latter is engaged by the lower gripper cylinder 34, whereupon the suction means release the sheet by admission of air thereto and move backward ahead of the sheet engaged upon the lower gripper cylinder, so as to clear that sheet as it travels backwardly upward on the lower gripper cylinder.

The lower gripper cylinder 34 is shown to consist of a plurality of spaced sections: Two narrow sections 96 near the center of the machine, with a clearance space therebetween for the suction means, and two wider sections 97, the lower gripper cylinders proper. The upper gripper cylinder 17 comprises a central section 98 and two other sections 99, disposed upon both sides of said center section, which are the upper gripper cylinders proper.

Upon the inside faces of the two sides 12 and 13 of the frame are fixedly mounted two cams 100 and 101, substantially concentrically with the shafts 16 and 36 of the upper and lower gripper cylinders, respectively. Adjoining these cams, the two shafts 16 and 36 carry brackets 102 and 109; said brackets support the gear segments 103 at fulcrum points 104 and also the pinions 105 and 106 which are engaged by the gear segments 103. The gear segments and the rollers 108 are respectively engaged upon the grooves 110 and 111 of the cams 100and 101. As the upper and lower gripper cylinder shafts 16 and 36 rotate once, the grooves 110 and 111 of the respective stationary cams 100 and 101 swing the gear segments 103 back and forth, through one cycle of oscillation for each revolution of the respective shafts. This rotates the respective pinions 105 and 106 through a cycle of opposite rotations, and these rotations are transmitted to the two gripper shafts 112 and 113 respectively, which extend from the brackets 102 and 109 to the right and to the left, respectively, through the respective cylinder sections. The upper and lower grippers 114 and 115 are mounted in suitable openings (not shown) in the up- 195 per and lower cylinder sections 97 and 99, respectively, said openings being of such width, that the grippers may be swung from their gripper positions, as respective shown in Figs. 1 and 6, back into said sections. The gripper jaws 116 11 and 117 of the grippers 114 and 115 rest in the respective gripper positions upon the cylindrical surfaces of the cylinders 17 and 34.

The lower grippers 115 are swung in counterclockwise direction upon their shaft 113 by the 1. 5 cam 101 into the position they occupy in Fig. 1 in respect to the lower cylinder 34, when that shaft 113 travels down towards and past the stack of sheets 43, so that the top sheet 44, which has been picked up by the suction head 92, is en- 120 gaged by the jaws 117 of said grippers. The top sheet is now carried away by the lower gripper cylinder 34, the suction means having released the top sheet 44 and having been swung out of its way. After the lower gripper cylinder 34 has travelled through approximately in clockwise direction, the position of Fig. 1 is reached. Upon further rotation of the lower gripper cylinder, the sheet carried thereby is brought into engagement between the upper and lower cyling, ders 17 and 34, in rolling mill fashion, whereupon it is released by the grippers 115 of the lower gripper cylinder 34. But in the meantime, the grippers 114 of the upper gripper cylinder have swung into action and are just about to engage upon the front edge of the sheet, when the position of Fig. 6 is reached.

Whereas the jaws 117 of the lower grippers 115 engage upon the surface of the top sheet 44 only, when they seize it and carry it along, said sheet comes also,-when the position of Fig. 6 is reached,into touch with the radially disposed back 118 of grippers 114 which adjoins the jaws 116. The back faces 118 of the upper grippers 114 push the front edge of the sheet slightly back, A55. against the direction of its travel, before the jaws 116 positively grip the sheet, the sheet being buckled, outwardly from cylinder 17 as indicated in Fig. 6, between said front edge engaged by jaws 116 and the point at which it is frictionally t tion.

' sheet from the pick-up device to a gripper cylinengaged between the upper and lower gripper cylinders 17 and 34. The front edge of the sheet is thereby placed into a cyclically definite angular position upon the upper gripper cylinder, the sheet thus being absolutely registered for the purpose of subsequent operations to be performed fter it has left the feeding device. If the sheet had been engaged to a slightly greater or lesser extent below the jaws 117 of the lower grippers 115 when it was transferred onto the lower gripper cylinder 34, from the suction pick-up device, and was therefore not in absolute registry in respect to the cycle of the feeding device, its front end is buckled to a greater or lesser extent when it reaches the position of Fig. 6, the front edge of the sheet being brought into a position of accurate angular alignment upon the upper gripper cylinder 17. Incidentally the front edge is also brought into rectangular alignment with the direction of travel, if the sheet previously was not in such. an alignment, the front end of the sheet being buckled more by the gripper 11%, in one or the other section 97 of the upper cylinder 17, the back 118 of which it strikes first.

After the sheet has been engaged upon the upper cylinder in the position of Fig. 6, it is swung up thereby in counter-clockwise direction into engagement by the rollers 24, the buckle having been removed from the sheet, as soon as its rear end had been removed from engagement between the pair of gripper cylinders 17 and 34. While thus passing up on the upper gripper cylinder 17, the disc applies paste to the right edge of the sheet which is then delivered from an engagernent between the upper gripper cylinder 17 and the rollers 24 into the feed rollers 18 and 1e and from there, backwardly, into the envelope making machine.

The sheet raiser of my invention is a device, which interlocks with the above outlined opera- Whereas the operation of the grippers in connection with the two gripper cylinders is similar to that disclosed in respect to one such grip per cylinder in my prior patent, and may be understood more fully by reference to said patcut, my sheet raisers are a new part in respect to which there is no equivalent in my prior patent. It does away with retarding and buckling operations which in the prior art were resorted to for the purpose of facilitating the transfer of the der. It accomplishes more than could ever be performed by such operations in the prior art, because it makes possible the handlingof larger and thinner sheets.

The sheet raiser is, for claritys sake, not shown in the assemblies of Figs. 1 and 2, since, if shown in Fig. 1, it would overlap the showing of the suction means. It is separately disclosed in Figs.

. 3 and 4, in which only the suction head 92 indi cates the relative position of the suction pick-up device. The sheet raisers comprise annular sectors 119 which by a suitable connecting piece 120 are mounted upon the upper ends of shafts 121, These shafts 121 are rotatably supported in vertical bearings 122, which arise from a cross bar 123 extending transversely to the frame of the machine andmounted upon the sides 12 and 13.

Below the sheet raisers, the gear pinions 124 are mounted upon the shafts 121; they mesh into the gear segments 125 which are fulcrumed by means of shafts 126 upon bearings 127 vertically extending from the cross bars 128 extending transversely to and connecting the sides 12 and 13 of the frame. Downward from the gear segments 125 extend rollers 129 substantially in alignment with the cam shaft 38 and engaged upon grooves in the cylindrical box cams 130 which are mounted upon said shaft 38. The grooves of the box cams are oppositely disposed to each other, in substantial symmetry.

When at rest, the sheet raisers are completely withdrawn from the stack of sheets 43. As soon as the suction pick-up device lifts up the top sheet 44, near the center of its front edge, the sheet raisers are swung by the respective gear segments below said top sheet, above the stack 13 of sheets, the sheet raisers assuming their position of Fig. 3 at the beginning of the operation. The free ends of the sheet raisers swing around the shafts 121 away from each other, below the top sheet, said sheet raisers having the shape of annular sectors in order to clear the upper ends of bars in thus swinging towards the sides of the sheet 14 below the front edge thereof. By this operation, the greater part of the front edge of the sheet is lifted up from the stack of sheets 43, and may therefore be readily engaged upon by the gripper 115 of the lower cylinder 34 and may readily glide above the top of the bars as, when pulled away by the lower gripper cylinder 34, even if the sheets are v ry light and of considerable width. The annular sector 119 of the sheet raiser preferably extends helically downward towards its free end, so that the top sheet at is raised slightly higher near its center juxtaposite the pick-up device, while the sheet raisers swing away from each other below the top sheet 4. 1. After the top sheet 44 has been removed from the stack as, drawn from their position of extension over the stack of sheets by the reversal of the rotation of pinions 12 1, so that the sheet raisers clear the stack 43, when the next top sheet 44 is engaged upon and lifted up by the suction pick-up device.

While I have shown and described my invention with some degree of particularity, it will be realized that other modifications and changes may be resorted to underspecial conditions. I

therefore do not wish to be limited and restricted to the exact details shown and described, but reserve the right to make such changes and modifications as may fairly fall within the scope of the subject matter now being claimed.

What I claim is:

1. In a device for feeding sheets from a stack of sheets of flexible material, pick-up means separating the upwardly clear and exposed edge of one side of the top sheet of said stack of sheets from said stack, and a circularly disposed sheet-raiser with a free end uxtaposite said stack of sheets and said pick-up means and rotatably fulcrumed at a point juxtaposite said stack of sheets, said free end of the sheet-raiser being inserted by rotation of said sheet-raiser between said separated top sheet and said stack of sheets, whereby said top sheet is separated to a greater width along the said edge from said stack of sheets.

2. In a device for feeding sheets from a stack of sheets of flexible material, pick-up means separating the upwardly clear and exposed edge of one side of the top sheet of said stack of sheets from said stack, and a helically disposed the sheet'raisers are withsheet-raiser with a free end juxtaposite said being inserted y rotation of said sheet-raiser between said separated top sheet and said stack 6f sheets, whereby said top sheet is separated to a greater width along the said edge from said stack of sheets.

3. In a device for feeding sheets from a stack of sheets of flexible material, pick-up means separating the top sheet of said stack of sheets from said stack at one edge of said sheet, a pair of circularly disposed sheet-raisers with free ends juxtaposite said stack of sheets and said pick-up means and rotatably fulcrumed at points juxtaposite said stackof sheets, said sheet raisers normally clearing said stack of sheets vertically, and a driving mechanism to which said sheet raisers are oppositely rotatably con-- nected, said free ends of the sheet-raisers being adapted to be inserted by rotation of said sheet-raisers between said separated top sheet and said stack of sheets, whereby said top sheet is raised and separated to a greater width along the said edge from said stack of sheets.

4. In a device for feeding sheets from a stack of sheets of flexible material, pick-up means separating the top sheet of said stack of sheets from said stack at one edge of said sheet, a pair of helically disposed sheet-raisers with free ends juxtaposite said stack of sheets and said pickup means and rotatably fulorumed at points juxtaposite said stack of sheets, and a driving mechanism to which said sheet-raisers are oppositely rotatably connected, said free ends of the sheet-raisers being adapted to be inserted by rotation of said sheet-raisers between said separated top sheet and said stack of sheets, whereby said top sheet is separated to a greater width and gradually and uniformly raised along the said edge from said stack of sheets.

5. In a device for feeding sheets from a stack of sheets of flexible material, pick-up means separating the top sheet of said stack of sheets from said stack at one edge of said sheet, a pair of circularly disposed sheet-raisers with free ends juxtaposite said stack of sheets and said pick-up means and rotatably fulcrumed at points juxtaposite said stack of sheets, and a driving mechanism to which said sheet-raisers are oppositely oscillatably connected, said free ends of the sheet-raisers being adapted to be inserted by rotation of said sheet-raisers in one direction between said separated top sheet and said stack of sheets, whereby said top sheet is separated to a greater width along the said edge from said stack of sheets, said free ends slidably contacting with said top sheet and continuously and uniformly raising said sheet while thus contacting therewise during said respective rotation in one direction of one cycle of said oscillations.

6. In a device for feeding sheets from a stack of sheets of flexible material, pick-up means separating the top sheet of said stack of sheets from said stack at one edge of said sheet, a pair of sheet-raisers with free ends rigidly extending along the path of a helix juxtaposite said stack of sheets and said pick-up means and rotatably fulcrumed at points juxtaposite said stack of sheets, and a driving mechanism to which said sheet-raisers are oppositely oscillatably connected, said free ends of the sheet-raisers being adapted to be inserted by rotation of said sheetraisers in one direction between said separated top sheet and said stack of sheets, whereby said top sheet is separated to a greater width along the said edge from said stack of sheets.

7. In a device for feeding sheets from a stack of sheets of flexible material, pick-up means separating the top sheet of said stack of sheets from said stack at one edge of said sheet, a pair,

of sheet-raisers having substantially the shape of annular sectors with free ends juxtaposite said stack of sheets and said pick-up means and rotatably fuicrumed at points juxtaposite said stack of sheets, and a driving mechanism to which said sheet-raisers are oppositely oscillatably connected, said free ends of the sheetraisers being inserted by rotation of said sheetraisers in one direction between said separated top sheet and said stack of sheets, whereby said top sheet is the said edge from saidstack of sheets, and is continuously raised where said annular sectors slidingly contact therewith.

8. In a device for feeding sheets from a stack of sheets of flexible material, in combination with suction-operated pick-up means separating the upwardly unobstructed edge of the top sheet from said stack, with a cylinder with a gripper bar and grippers attached to it which is adapted to carry away a sheet after it has been lifted up from said stack, and with an elevator raising said stack into a position of operative relation to said means and said cylinder, a pair of oppositely oscillating sheet-raisers lifting said top sheet from said stack and gradually raising it in respect thereto.

9. In a device for feeding sheets from a stack of sheets of flexible material, in combination with suction-operated pick-up means separating the edge of the top sheet from said stack, with a cylinder with a gripper bar and grippers attached to it which is adapted to carry away a sheet after it has been lifted up from said stack, and with an elevator raising said stack into a position of operative relation to said means and said cylinder, a pair of oppositely oscillating sheet-raisers arranged on both sides of said pick-up means and lifting said top sheet from said stack.

10. In a device for feeding sheets from. a stack of sheets of flexible material, in combination with means lifting the top sheet from said stack, and with a cylinder with a gripper bar and grippers attached to it which is adapted to carry away said lifted top sheet, a second cylinder with a gripper bar and grippers attached to it which tangentially merges with said first cylinder and which is adapted to receive from said first cylinder and to carry away said top sheet.

11. In a device for feeding sheets from a stack of sheets of flexible material, in combination with means lifting the top sheet from said stack, a pair of tangentially merging, operatively coupled cylinders adapted to engage said sheets between each other in rolling mill fashion, gripper means on said cylinders, a mechanism actuating the gripper means on one of said cylinders to engage upon said lifted top sheet and to feed it into engagement between said two cylinders, and a mechanism actuating the gripper means on the second cylinder to engage upon said sheet when it is engaged between said cylinders.

12. In a device for feeding sheets from a stack of sheets of flexible material, in combination with means lifting the top sheet from said stack, a pair ofv tangentially merging, operatively coupled cylinders adapted to engage said sheets between each other in rolling mill fashion, gripper means on said cylinder to engage upon said lifted top sheet and to feed it into engagement between said two cylinders, and a mechanism actuating the gripper means on the second cylinder to bear against the edge of and to engage upon said sheet when it is engaged between said cylinders,

separated to a greater width along 13. In a device for feeding sheets from a stack of sheets of flexible material, in combination with means lifting the top sheet from said stack, a pair of tangentially merging, operatively coupled cylinders adapted to engage said sheets between each other in rolling mill fashion, gripper means on said cylinder to engage upon said lifted top sheet and to feed it into engagement between said two cylinders, and a mechanism actuating the gripper means on the second cylinder to bear against the edge of said sheet when it is engaged between said cylinders, and to engage it in an angularly predetermined position upon said second cylinder.

14. In a device for feeding sheets from a stack, a rotatable sheet-raiser mounted alongside of but normally removed and disengaged from said stack, pick-up means spacedly separating the top sheet from said stack, said separated sheet being free from any weight on its outer surface, and a mechanism cyclically actuating said means and swinging said sheet-raiser over said stack, so that said sheet-raiser is inserted between the said stack and the said separated top sheet and raises said top sheet.

15. In a device for feeding sheets from a stack, a rotatable sheet-raiser mounted alongside of but normally removed and disengaged from said stack and always upwardly clearing the top sheet of said stack, pick-up means independent of said raiser and spacedly separating the top sheet from said stack, said separated sheet being free from any weight on its outer surface, and a mechanism cyclically actuating said means and swinging said sheet-raiser over said stack, so that said sheet-raiser is inserted between the said stack and the said separated top sheet and raises said top sheet. v

16. In a device for feeding sheets from a stack, a rotatable sheet-raiser mounted alongside of but normally removed and disengaged from said stack, pick-up means spacedly separating the top sheet from said stack, said separated sheet being free from any weight on its outer surface, and a mechanism cyclically actuating said means and swinging said sheet-raiser over said stack, so that said sheet raiser is inserted between the said stack and the said separated top sheet, said raiser being moved and being shaped to slide on the bottom side of said sheet and continuously to raise said sheet where it slides thereon, while thus being inserted.

1'7. In combination with the support of a stack of sheets to be fed into a machine, a shaft inclined relatively to said support and rotatably mounted juxtaposite said stack, and a sheet-raiser mounted on said shaft, swung into engagement between sheets of said stack by rotation of said shaft, and raising some of said sheets when thus swung, said sheets being free from any weight on their outer surface.

18. In combination with the support of a stack of sheets to be fed into a machine, a shaft inclined relatively to said support and towards said stack and rotatably mounted juxtaposite said stack, and a sheet-raiser mounted on said shaft,

swung into engagement between sheets of said stack by rotation of said shaft and raising some of said sheets when thus swung, said sheets being free from any weight on their outer surface.

19. In combination with the support of a stack of sheets to be fed into a machine, a shaft inclined relatively to said support and rotatably mounted juxtaposite said stack, and a helix mounted on said shaft, swung into engagement between sheets of said stack by rotation of said shaft, and raising some of said sheets when thus swung, said sheets being free from any weight on their outer surface.

20. In combination with the support of a stack of sheets to be fed into a machine and an upright against which rest the front edges of said sheets, a sheet-raiser rotatably mounted juxtaposite said stack, and a free end forming part of said raiser disposed substantially concentric to the axis of rotation thereof and swung between sheets of said stack in back of said upright by rotation of said sheet-raiser.

21. In a device for feeding sheets from a stack of sheets of flexible material, pick-up means separating the top sheet of said stack of sheets from said stack at one edge of said sheets, said separated sheet being free from any weight on its outp er surface, a sheet-raiser with a free, flat end juxtaposite said stack of sheets and said pick-up means, the inclined top surface of said sheet raiser being disposed at an angle in respect to said stacked sheets, and means endwise inserting 1 said sheet-raiser between said stack of sheets and said edge of said unblistered and unbuckled top sheet, whereby said top sheet is gradually raised and separated to a greater width along the said edge from said stack of sheets.

22. In a device for feeding from a stack of sheets of flexible material, pick-up means separating the top sheet of said stack of sheets from said stack at one edge of said sheet, said separated sheet being free from any weight on its 1 outer surface, a sheet-raiser with a free end juxtaposite said stack of sheets and said pick-up means, and means endwise downwardly inserting said sheet-raiser between said stack of sheets and said edge of said top sheet, and laterally moving said inserted sheet-raiser at an angle in respect to the direction of said endwise insertion between said unblistered and unbuckled top sheet and said stack of sheets, whereby said top sheet is gradually raised and separated to a greater width along the said edge from said stack of sheets.

23. In a device for feeding sheets from a stack of sheets of flexible material, pick-up means separating the top sheet of said stack of sheets from said stack, said separated sheet being free from any weight on its outer surface, a pair of sheetraisers with free ends juxtaposite said stack of sheets and said pick-up means, and means endwise inserting the free ends of said sheet-raiser between said stack of sheets and one edge of 1 2- 

